Fix for autobuild failure: forgotten ';' (bison 1.875 accepts if it's not there, but 1.75 does not)

sql/sql_yacc.yy:
  forgotten ';' (bison 1.875 accepts if it's not there, but 1.75 does not)

sql/sql_yacc.yy

@@ -2111,6 +2111,7 @@ start_transaction_opts:
         {
            $$= MYSQL_START_TRANS_OPT_WITH_CONS_SNAPSHOT;
         }
+        ;
 
 slave_thread_opts:
 	{ Lex->slave_thd_opt= 0; }